This invention is generally directed to a system for encasing materials in plastic bags. A preferred embodiment will be described in which whole poultry is encased in plastic bags. The invention, however, can be used to encase other materials, such as cut-up poultry, whole-muscle meats, cheeses, and non-food items.
The poultry industry sells fowl either as whole dressed birds or as cut-up parts. A consumer can buy a whole dressed chicken in a grocery store, can buy one dressed chicken cut up into parts, or can buy a package of, for example, just legs or just wings. In the two latter situations, the chicken parts are conventionally placed on a disposable tray, typically a plastic or foam material, in order to hold the parts together. Some poultry producers place whole dressed birds on these trays also. The poultry is then encased in plastic, either by a heat-seal process or a plastic bag.
In the heat-seal process, the tray and the poultry (or sometimes just the poultry) are placed in a bag made of a heat-shrinkable material. Sometimes the bag is gathered at its opening to form a neck and a clip is applied to the gathered neck to seal the poultry inside the bag. The bag is then exposed to heat, shrinking the bag around the poultry. This process wraps the product very tightly. In the case of products such as poultry, a tighter package presents a better appearance to consumers.
In the bagging process, the tray and the poultry (or sometimes just the poultry) are placed in a bag, the bag is gathered at its opening to form a neck, and a clip is applied to the gathered neck to seal the poultry inside the bag. This process has the advantage that the heat-shrinking process does not distort markings on the bag.
It is known in the art to use a bagging machine to place poultry in bags, either regular plastic bags or heat-shrinkable bags. Conventional bagging machines have a pair of opposed product horns, movable in a horizontal plane toward and away from each other. Poultry is placed, by hand or by automatic means, in between the product horns, which are in a first position adjacent to each other. A bag is placed over the product horns, which then move away from each other, opening the mouth of the bag wide enough to accommodate the poultry. The poultry is then pushed into the bag, either by hand or by automatic means, such as a ram. Continued pushing of the poultry causes the poultry to push against the bottom of the bag, causing the now-bagged poultry to move out of the space between the two product horns. The now-bagged poultry then is moved, by hand or by automatic means, to a clipping station and/or a heat-shrinking station.
Heat-shrinkable bags conventionally are supplied in a series on a pair of tapes, as will hereinafter be described in more detail. A string of rollers pulls the series of bags to the opening of the product horns. Regular bags are supplied in a stack, typically on a wicket, as will hereinafter be described in more detail. A bag carriage unit carries the stack of bags to the opening of the product horns.
Baggers can place poultry or other material in either type of bag, but the equipment to place the bag at the mouth of the product horns differs for the two types of bags. A processor who packages material in both types of bags may choose to have two bagging systems, which requires more capital investment and may result in one or the other system incurring substantial downtime if there is a demand only for the output of one system at a time. Otherwise, a processor may use one bagger but have two separate pieces of equipment to bring the bags to the product horns. This option incurs substantial downtime to stop the line, remove the one piece of equipment, and connect the other piece of equipment.
There is a clear advantage to being able to switch between types of bags with as little downtime as possible. The present invention provides this advantage.